Anti-stalling composition



United States Patent 3,138,018 ANTi-STALHNG COWOSTTION John De Witt Rogers, In, Hoehessin, Deh, and Harold Joseph Scheule, Weodstown, NJ assignors to E. I. du Pont de Nemours and Ccmpany, Wilmington, Del, a corporation oi Delaware No Drawing. Filed Sept. 12, 1962, Ser. No. 223,584 3 (Ilainrs. (Cl. 4472) This invention is directed to petroleum distillate fuels having improved performance in internal combustion engines under cool, humid atmospheric conditions.

A common occurrence in the operation of an internal combustion engine at temperatures between about 30 F. and 60 F. and at high humidity is frequent engine stalling during the engine warm-up and during engine idling. This effect, referred to as carburetor icing, is attributed to the formation of ice particles in the carburetor, especially on the throttle plate and surrounding walls. The formation of ice in the carburetor is caused by a reduction in the temperature of the metal parts of the carburetor as the fuel vaporizes, thereby causing the moisture in the air to condense on the metal parts of the carburetor and freeze. Ice formation at the edge of the throttle plate reduces air flow to the engine, thus causing the engine to stall. Ice formation on the air bleeds or venturi cause the engine to stall from excessively rich mixtures.

It is, therefore, an object of the present invention to provide a significantly improved distillate fuel having a reduced tendency to stall in cool, humid weather.

It has been found that upon addition of small amounts of a selected combination or" certain alkanesulfonamides and certain amine salts of alkyl esters of orthophosphoric acids to a distillate fuel, stalling of the engine during Warm-up and idling is greatly reduced.

More specifically, the present invention is directed to petroleum distillate fuels containing 0.0005 to 0.01 Weight percent of a selected combination of (1) 20 to 50 weight percent of an amine salt of a branched chain primary aliphatic acid ester of orthophosphoric acid in which each esterifying alkyl group contains 8 to 16 carbon atoms and the amine is an aliphatic hydrocarbon monoamine of 6 to 18 carbon atoms and (2) 80 to 50 weight percent of an N-tertiary alkyl alkanesulfonamide having the structure RSO NHR', Where R is an alkyl radical of 12 to 20 carbon atoms and may contain chlorine, or a mixture of such radicals, and R is a tertiary alkyl radical having 8 to 15 carbon atoms, or a mixture of such radicals.

A preferred embodiment of the present invention is the heretofore described select combination of an amine salt and N-tertiary alkyl alkanesulfonamide, wherein the weight ratio of phosphate to sulfonamide is 1:4.

A further preferred embodiment of the present invention is a petroleum distillate fuel containing the heretofore described select combination of an amine salt and N-tertiary alkyl alkanesulfonamide, wherein the amine salt is the C C aliphatic monoamine salt of tridecylphosphate and the alkanesulfonamide is the N-tertiary O -C alkyl White Oil sulfonamide.

The amine salts which form part of the novel select combination of the present invention are normally liquid neutral amine salts of branched chain primary alkyl acid esters of orthophosphoric acid in which each esterifying alkyl group contains 8 to 16 carbon atoms and the arnine is an aliphatic hydrocarbon monoamine of 6 to 18 carbon atoms in which each aliphatic hydrocarbon radical is attached to the nitrogen through a saturated carbon atom.

These amine salts may be prepared, according to any of the methods of the art, by neutralizing primary alkyl acid phosphates with the monoamine. Normally, a molecule of amine is used for each molecule of the phosphate to produce a salt exerting a substantially neutral pH (6-7).

The branched chain primary alkyl acid esters of orthophosphoric acid (acid phosphates) will be understood to be those esters in which only 1 or 2 of the three acidic hydrogen atoms of orthophosphoric acid have been replaced by the alkyl groups, i.e., the monoalkyl dihydrogen phosphates and the dialkyl hydrogen phosphates. Such esters may be obtained according to the general methods of the art which involve reacting an alcohol with phosphorus pentoxide (P 0 From about 2 to about 4 moles of the alcohol may be used per mole of P 0 Preferably, about 3 moles of the alcohol per mole of P 0 will be used to yield approximately equimolar mixtures of the monoand dialkyl esters of orthophosphoric acid, containing about 40 to about 60 mole percent or" the monoalkyl esters and about 60 to about 40 mole percent of the dialkyl esters. These mixtures of mono and dialkyl esters are preferred for reasons of economy but other mixtures, as well as the single monoalkyl esters and single dialkyl esters, may also be used.

For the preparation of the branched chain primary alkyl acid phosphates, the alcohol will be a branched chain primary alkanol having 8 to 16 carbon atoms or a mixture of two or more of such alkanols. These alcohols preferably will be the branched chain primary alkanols made by the well-known Oxo-process from C0, H and a branched chain olefin such as the C -C monoolefinic polymers and interpolymers of propylene and butylene, as described for example in US. Patent 2,824,836 and in US. Patent 2,884,379. Examples of preferred Oxoalcohols that may be used are isooctyl alcohol from the propylene-butylene dimer, branched tridecyl primary alcohols from triisobutylene and from tetrapropylene, and the branched hexadecyl primary alcohols from pentapropylene. Other branched chain primary alkanols that can be used are those that may be prepared by alkaline condensation of two primary alkanols, having the structure RCI-l CI-I OH wherein R is alkyl and totalling 2 to 6 carbon atoms, to produce branched primary alkanols that are branched in the 2-position, for example, RCH CH CHRCH OH. For example, 2-hexyldecanol- 1 is produced by heating n-octanol with caustic and zinc dust, and similarly, 2-ethylhexanol-1 from butanol-l, as described in US. Patent 2,457,866. Other alcohols, that may be prepared by the latter and other methods known in the art and used to prepare phosphates according to the present invention, are of the formula where R is the same or diiferent alkyl group, each having from 2 to 6 carbon atoms. The branched alcohols may also be prepared by the conventional aldolization of suitable aldehydes followed by hydrogenation. In this way, the well-known oxo octaldehyde, which is obtained from heptene-l, CO and H and which is a mixture consisting very largely of dirnethylhexaldehydes, ethylhexaldehydes, and methylheptaldehydes containing the grouping is converted into Z-hexyldecanol, R'CHRCH OH, where R stands for C alkyl groups such as dimethylbutyl, methylpentyl, and ethylbutyl, and R stands for C alkyl groups such as dimethylhexyl, ethylhexyl and trimethylpentyl groups.

The amines that are used to produce the novel salts of this invention are the aliphatic hydrocarbon monoamines containing a total of 6 to 18 carbon atoms in which each aliphatic hydrocarbon radical is attached to the nitrogen through a saturated carbon atom. The term aliphatic hydrocarbon monoamine will be understood to mean a compound which contains only one amino nitrogen to which is :attached 1 to 3 aliphatic hydrocarbon radicals. Thus, the amines may be primary, secondary, or tertiary amines, with the primary amines usually being preferred. Usually, the water-insoluble amines will be preferred. The aliphatic hydrocarbon radicals attachedto the nitrogen may be acyclic (open chain) or alicyclic (cycloaliphatic) radicals. Also, the aliphatic hydrocarbon radical may be a saturated or an unsaturated radical, provided that the carbon atom which is attached to the nitrogen atom is a saturated carbon atom; that is, the carbon atom that is attached -to the nitrogen must not be attached by a multiple bond. Preferably, the amine will be an alkyl (acyclic, saturated) monoamine of 6 to 18 carbon atoms and most preferably of 8 to 14 carbon atoms. Also, preferably, when the amine is a secondary amine, it will contain a total of at least 8 carbon atoms and, when it is a tertiary amine, it'will contain a total of at least 10 carbon atoms.

Examples of suitable primary amines are: hexylarnine; cyclohexylamine; octylamine; 2-ethylhexylamine; laurylamine; hexadecylamine; t-dodecylamine; octadecenylamine; octadienylamine; l,1,3,3-tetramethylbutylamine (t-octylamine); the mixed t-alkyl primary amine fractions having from 12 to 14 carbon atoms, such as those marketed under the trademark Primene 81-R; t-nonylamine, also available commercially, consisting mainly of the C amine with small amounts of the C and C amines; cocoamine, a mixture of -0 n-alkyl primary amines with the C amine predominating; and tallowamine, a mixture of stearyl, palrnityl and oleyl amines. Examples of useful secondary amines are di-n-butylamine, di-sec.-butylamine, diisobutylamine, diamylamine, di-2- ethylhexylamine, diisooctylamine, N-n-octenylcyclohexylamine, and dicyclohexylamine. Examples of suitable tertiary amines are: tributylarnine, trihexylamine, N,N- diethylcyclohexylamine, and N,N-dimethyloleylamine.

Any of the above amines may be. employed in salt formation with any of the above branched chain alkyl acid phosphates. Preferred, however, are 2-ethylhexylamine, t-dodecylamine, coco-amine, the mixed t-alkyl primary amine fractions containing 12 to 14 carbon atoms, t-octylamine and t-nonylamine.

It should be noted that the preferred amines employed according to the invention are water-insoluble and oilsoluble.

Some useful examples of the amine salts of this invention are: l2-ethylhexylammonium isooctyl phosphate, 2- ethylhexylammonium tridecyl phosphate, tertiary-octylammonium tridecyl phosphate, tertiary-nonylammonium 0x0 hexadecyl phosphate, mixed tertiary-C -C alkylammonium isooctyl phosphates, and'rnixed tertiary-C C alkylammonium tridecyl phosphates.

The sulfonamides utilized according to the present invention are N-tertiary alkyl alkanesulfonamides having the structure RSO NHR wherein R is a saturated alkyl radical having 12 to 20 carbon atoms and may contain chlorine, or a mixture of such alkyl radicals, and R is a tertiary alkyl group having 8 to 15 carbon atoms, or a mixture of such alkyl groups. R may be dodecyl, rnyristyl, cetyl, stearyl, eicosyl or mixtures of alkyl groups having 12 to 14, 14 to 16, or 16 to 20 carbon atoms, hydrocarbon groups derived from white oil, petrolatum or mixtures of such hydrocarbon groups. R is derived from a tertiary alkyl monoamine and has the structure where the tertiary carbon atom is bonded to the nitrogen atom, and may be tertiary-octyl, tertiary-nonyl or a mixture of tertiary alkyl groups having 12 to 14 carbon atoms. Representative examples of such compounds are N- tertiary octyl stearylsulfonamide, N-tertiary dodecyl white oil-sulfonamide, 'N-tertiary-octyl dodecylsulfonamide, N-tertiary-octyl white oil-sulfonamide, N-tertiarynonyl white oil-sulfonamide, N-te'rtiary-C C alkyl White oil-sulfonamide, N-tertiary-octyl hexadecylsulfonamide, and N-tertiary-nonyl deodorized kerosene sulfonamide.

The sulfonarnides may be prepared by any known methods for the preparation of sulfonamides. They are conventionally prepared by starting with the aliphatic hydrocarbon desired and reacting with gaseous sulfur dioxide and chlorine in the presence of actinic light to obtain the hydrocarbon sulfonyl chloride, as described in U.S. Patents 2,046,090 and 2,202,791. The hydrocarbon sulfonyl chloride thus obtained may be further reacted with the desired amine by conventional techniques, as set forth in US. Patent 2,334,186. Preferably the hydrocarbon sulfonyl chloride used for the preparation of the sulfork' amides is derived from the sulfochlorination of a commerically available petroleum hydrocarbon, such asNo. 40 white oil, which is a highly acid-washed paraffinic petroleum fraction having an average of 16 to 20 carbon atoms, of the following inspection data:

Acid wash test, color 2.0

Specific gravity, 16 C./16 C 0.810.

Distillation range:

5% distilled C 284 50% distilled C 300 distilled C 342 Viscosity at F., SUS 36 For the prepartion of the sulfonamide, readily available tertiary-alkyl primary amines are preferred, of the formula where R is an alkyl radical having an average of5 to 12 carbon atoms. Examples of the tertiary alkylamines used to prepare the sulfonamides are 1,1,3,3-tetramethylbutylamine (tertiary-octylamine) the mixed tertiary alkylamine fractions having 12-14 carbon atoms, such as those marketed commercially under the trademark Primene 8l-R, and tertiary nonylamines, also available commercially, consisting mainly of the C amine with small amounts of C and C amines, and having a molecular weight range of 143-157.

The selected combination of the invention is. composed of the above described amine salts and alkanesulfonamides. This combination, effective as an anti-stall additive in gasoline, is used in concentrations varying from 0.0005 to 0.01 percent by Weight of the fuel. The weight ratio of amine salt to sulfonamide varies between 1:1 to 1:4 respectively. Preferably the Weight ratio of amine salts to sulfonamide is 1:4.

A representative example illustrating the presentinvention follows.

Example The anti-stalling properties of the select combination of the invention were demonstrated in a 6-cylinder Chevrolet engine, horsepower rating 86 at 3400 r.p.m. and displacement of 216.5 cu. in. The test conditions were as follows:

Intake air 38-40 F. Relative humidity Approx. 100%.. Engine load 10 horsepower. Engine speed 1500 r.p.m. Idle speed 350-400 r.p.m. Fuel Temperature to carburetor 50-55 F.

Lbs. Additive/1,000 bbls. Fuel Additive 1 Fuel A Fuel B Fuel Fuel D 1. (lirc tertiary alkylamine salt of trideoyl phosphate 5. 0 3. 0 3. 10. O

2. N-CmOn-tertiary alkyl White Oil sulfonamide 10 12 10 3. of (l) and 80% of (2) 2. 5 2. 0 1. 0-1. 5 5. 0

1 The additive is used as a solution of 80 parts of agent in 20 parts of kerosene.

It can be seen very readily from the above data that a smaller amount of the combination than either component alone is required to give comparable stall times. Although the amine salt of the phosphate has a greater efiect when used alone than the sulfonamide, yet it is surprising that even when the amine salt of the phosphate constitutes only 20% of the combination with the sulfonamide, it exerts a surprising eilect upon the sulfonamide such that the efiect of the combination is considerably greater than that of the amine salt alone. For example, only 2.5 lbs. of the select combination were required to prevent stalling for a minimum of 3 minutes in Fuel A, while 5.0 lbs. of the amine salt and more than 10 lbs. of the sulfonamide were required to produce a comparable run time in the same fuel.

The various fuels used had the following ASTM dis- The unique and surprising effect of this additive combination is shown by mixtures containing about 20% to at least 50% by Weight of the amine-neutralized phosphate.

These additives may be used in fuels containing other additives, such as, antioxidants, anti-knock agents, antirust agents, dyes, metal deactivators and the like.

It is to be understood that the preceding example is representative and that said example may be varied within the scope of the total specification, as understood by one skilled in the art, to produce essentially the same results.

As many apparently widely different embodiments of this invention may be made Without departing from the spirit and scope thereof, it is to be understood that this invention is not limited to the specific embodiments thereof except as defined in the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An improved distillate fuel selected from the group consisting of gasoline and fuel oils containing from 0.0005 to 0.01 weight percent of (1) 20 to 50 weight percent of an amine salt of a branched chain primary aliphatic acid ester of orthophosphoric acid where each esterifying alkyl group contains 8 to 16 carbon atoms and the amine is an aliphatic hydrocarbon monoamine of 6 to 18 carbon atoms and (2) to 50 weight percent of a member selected from the group consisting of N-tertiary alkyl alkanesulfonamide and mixtures of N-tertiary alkyl alkanesulfonamides, said N-tertiary alkyl alkanesulfonamide having the structure RSO NHR', wherein R is selected from the group consisting of alkyl of 12 to 20 carbon atoms and chloroalkyl of 12 to 20 carbon atoms, and wherein R is tertiary allryl of 8 to 15 carbon atoms.

2. The improved distillate fuel of claim 1 wherein the ratio of phosphate to sulfonamide is 1:4.

3. The improved distillate fuel of claim 1 wherein the amine salt is the C C aliphatic monoamine salt of tridecylphosphate and the alkanesulfonarnide is N-tertiary C C alkyl white oil sulfonamide.

References Cited in the file of this patent UNITED STATES PATENTS 2,863,904 Cantrell et al. Dec. 9, 1958 2,906,613 Mills Sept. 29, 1959 FOREIGN PATENTS 534,147 Great Britain Feb. 28, 1941 791,397 Great Britain Mar. 5, 1958 

1. AN IMPROVEMENT DISTILLATE FUEL SELECTED FROM THE GROUP CONSISTING OF GASOLINE AND FUEL OILS CONTAINING FROM 0.0005 TO 0.01 WEIGHT PERCENT OF (1) 20 TO 50 WEIGHT PERCENT OF AN AIMINE SALT OF A BRANCHED CHAIN PRIMARY ALIPHATIC ACID ESTER OF ORTHOPHOSPHORIC ACID WHERE EACH ESTERIFYING GROUP CONTAINS 8 TO 16 CARBON ATOMS AND THE AMINE IS AN ALIPHATIC HYDROCARBON MONOAMINE OF 6 TO 18 CARBON ATOMS AND (2) 80 TO 50 WEIGHT PERCENT OF A MEMBER SELECTED FROM THE GROUP CONSISTING OF N-TERTIARY ALKYL ALKANESULFONAMIDE AND MIXTURES OF N-TERTIARY ALKYL ALKANESULFONAMIDES, SAID N-TERTIARY ALKYL ALKANESULFONAMIDE HAVING THE STRUCTURE RSO2NHR'', WHERE R IS SELECTED FROM THE GROUP CONSISTING OF ALKYL OF 12 TO 20 CARBON ATOMS AND CHLOROALKYL OF 12 TO 20 CARBON ATOMS AND WHEREIN R'' IS TERTIARY ALKYL OF 8 TO 15 CARBON ATOMS. 